1. Field of the Invention
This invention relates to detonators, and more particularly to an apparatus for reliably achieving detonation when there is a gap between the donor and acceptor charges and they are not in axial alignment.
2. Description of the Prior Art
The basic problem is that of obtaining the detonation of a second charge (the acceptor) upon the detonation of a first charge (the donor) where the two charges are separated by a gap or by a barrier and a gap and are axially offset from each other, i.e., they are not in perfect axial alignment. Detonation of the acceptor is achieved by the impact of the fragments of the exploded casing of the donor upon the acceptor casing with sufficient velocity and in a high enough density pattern. Thus the axial and lateral components of the distance separating the two charges are key variables because of their direct effect upon the aforementioned impact velocity and pattern.
Presently, detonators are typically comprised of donor and acceptor charges that are cylindrically shaped with flat ends that face each other. To ensure reliable detonation of the acceptor charge, it is desirable to axially align the two charges, i.e., position the axis of revolution of the two cylinders on the same line. However, operative vibration, structural design constraints, and random error occurring in assembly often cause misalignment, i.e., offset, between the two.
Assembly errors are dealt with by tightening the tolerances and simply absorbing the reduction in production rate and concomitant increase in unit cost. Another approach is to increase the explosive charge of the donor. This increases the possibility of damage to surrounding structures and components and may necessitate the installation of protective shielding for such, thus increasing the weight, a crucial design variable in flight vehicles. A third technique is to increase the target area of the acceptor charge. Structural design constraints may negate this possibility; also, this approach will increase the explosive charge of the acceptor and thus the problem of providing shielding to avoid potential damage to adjacent structures and components arises.
In addition, detonation across a gap and with a considerable angle between the respective axes of revolution of the donor and acceptor charge cylinders, e.g., around a corner, is currently highly unreliable.
The present invention increases the reliability of transmitting detonation from one charge to another across an intervening gap or barrier when the two charges are not axially aligned by shaping the tip of the donor charge to cause its casing fragments to disperse with a significant radial as well as axial velocity component. The tip of the acceptor charge is also shaped in order to increase the impact density of the casing fragments originating from the tip of the donor charge.
Through the use of the present invention, detonation may reliably be obtained around corners as well as for virtually any angular orientation between two or more separated charges.